Re: [PATCH 18/33] virtio_net: receive_merageable() use virtnet_xdp_handler()

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Feb 02, 2023 at 07:00:43PM +0800, Xuan Zhuo wrote:
> receive_merageable() use virtnet_xdp_handler()
> 
> Meanwhile, support Multi Buffer XDP.
> 
> Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>

typo

> ---
>  drivers/net/virtio/main.c | 88 +++++++++++++++------------------------
>  1 file changed, 33 insertions(+), 55 deletions(-)
> 
> diff --git a/drivers/net/virtio/main.c b/drivers/net/virtio/main.c
> index d7a856bd8862..fb82035a0b7f 100644
> --- a/drivers/net/virtio/main.c
> +++ b/drivers/net/virtio/main.c
> @@ -483,8 +483,10 @@ int virtnet_xdp_handler(struct bpf_prog *xdp_prog, struct xdp_buff *xdp,
>  			unsigned int *xdp_xmit,
>  			struct virtnet_rq_stats *stats)
>  {
> +	struct skb_shared_info *shinfo;
>  	struct xdp_frame *xdpf;
> -	int err;
> +	struct page *xdp_page;
> +	int err, i;
>  	u32 act;
>  
>  	act = bpf_prog_run_xdp(xdp_prog, xdp);
> @@ -527,6 +529,13 @@ int virtnet_xdp_handler(struct bpf_prog *xdp_prog, struct xdp_buff *xdp,
>  		trace_xdp_exception(dev, xdp_prog, act);
>  		fallthrough;
>  	case XDP_DROP:
> +		if (xdp_buff_has_frags(xdp)) {
> +			shinfo = xdp_get_shared_info_from_buff(xdp);
> +			for (i = 0; i < shinfo->nr_frags; i++) {
> +				xdp_page = skb_frag_page(&shinfo->frags[i]);
> +				put_page(xdp_page);
> +			}
> +		}
>  		return VIRTNET_XDP_RES_DROP;
>  	}
>  }
> @@ -809,7 +818,7 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev,
>  	unsigned int xdp_frags_truesz = 0;
>  	struct page *page;
>  	skb_frag_t *frag;
> -	int offset;
> +	int offset, i;
>  	void *ctx;
>  
>  	xdp_init_buff(xdp, frame_sz, &rq->xdp_rxq);
> @@ -842,7 +851,7 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev,
>  				 dev->name, *num_buf,
>  				 virtio16_to_cpu(vi->vdev, hdr->num_buffers));
>  			dev->stats.rx_length_errors++;
> -			return -EINVAL;
> +			goto err;
>  		}
>  
>  		stats->bytes += len;
> @@ -861,7 +870,7 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev,
>  			pr_debug("%s: rx error: len %u exceeds truesize %lu\n",
>  				 dev->name, len, (unsigned long)(truesize - room));
>  			dev->stats.rx_length_errors++;
> -			return -EINVAL;
> +			goto err;
>  		}
>  
>  		frag = &shinfo->frags[shinfo->nr_frags++];
> @@ -876,6 +885,14 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev,
>  
>  	*xdp_frags_truesize = xdp_frags_truesz;
>  	return 0;
> +
> +err:
> +	for (i = 0; i < shinfo->nr_frags; i++) {
> +		page = skb_frag_page(&shinfo->frags[i]);
> +		put_page(page);
> +	}
> +
> +	return -EINVAL;
>  }
>  
>  static struct sk_buff *receive_mergeable(struct net_device *dev,
> @@ -919,13 +936,10 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
>  	xdp_prog = rcu_dereference(rq->xdp_prog);
>  	if (xdp_prog) {
>  		unsigned int xdp_frags_truesz = 0;
> -		struct skb_shared_info *shinfo;
> -		struct xdp_frame *xdpf;
>  		struct page *xdp_page;
>  		struct xdp_buff xdp;
>  		void *data;
>  		u32 act;
> -		int i;
>  
>  		/* Transient failure which in theory could occur if
>  		 * in-flight packets from before XDP was enabled reach
> @@ -983,69 +997,33 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
>  		err = virtnet_build_xdp_buff_mrg(dev, vi, rq, &xdp, data, len, frame_sz,
>  						 &num_buf, &xdp_frags_truesz, stats);
>  		if (unlikely(err))
> -			goto err_xdp_frags;
> +			goto err_xdp;
>  
> -		act = bpf_prog_run_xdp(xdp_prog, &xdp);
> -		stats->xdp_packets++;
> +		act = virtnet_xdp_handler(xdp_prog, &xdp, dev, xdp_xmit, stats);
>  
>  		switch (act) {
> -		case XDP_PASS:
> +		case VIRTNET_XDP_RES_PASS:
>  			if (unlikely(xdp_page != page))
>  				put_page(page);
> +
>  			head_skb = build_skb_from_xdp_buff(dev, vi, &xdp, xdp_frags_truesz);
>  			rcu_read_unlock();
>  			return head_skb;
> -		case XDP_TX:
> -			stats->xdp_tx++;
> -			xdpf = xdp_convert_buff_to_frame(&xdp);
> -			if (unlikely(!xdpf)) {
> -				netdev_dbg(dev, "convert buff to frame failed for xdp\n");
> -				goto err_xdp_frags;
> -			}
> -			err = virtnet_xdp_xmit(dev, 1, &xdpf, 0);
> -			if (unlikely(!err)) {
> -				xdp_return_frame_rx_napi(xdpf);
> -			} else if (unlikely(err < 0)) {
> -				trace_xdp_exception(vi->dev, xdp_prog, act);
> -				goto err_xdp_frags;
> -			}
> -			*xdp_xmit |= VIRTIO_XDP_TX;
> -			if (unlikely(xdp_page != page))
> -				put_page(page);
> -			rcu_read_unlock();
> -			goto xdp_xmit;
> -		case XDP_REDIRECT:
> -			stats->xdp_redirects++;
> -			err = xdp_do_redirect(dev, &xdp, xdp_prog);
> -			if (err)
> -				goto err_xdp_frags;
> -			*xdp_xmit |= VIRTIO_XDP_REDIR;
> +
> +		case VIRTNET_XDP_RES_CONSUMED:
>  			if (unlikely(xdp_page != page))
>  				put_page(page);
> +
>  			rcu_read_unlock();
>  			goto xdp_xmit;
> -		default:
> -			bpf_warn_invalid_xdp_action(vi->dev, xdp_prog, act);
> -			fallthrough;
> -		case XDP_ABORTED:
> -			trace_xdp_exception(vi->dev, xdp_prog, act);
> -			fallthrough;
> -		case XDP_DROP:
> -			goto err_xdp_frags;
> -		}
> -err_xdp_frags:
> -		if (unlikely(xdp_page != page))
> -			__free_pages(xdp_page, 0);
>  
> -		if (xdp_buff_has_frags(&xdp)) {
> -			shinfo = xdp_get_shared_info_from_buff(&xdp);
> -			for (i = 0; i < shinfo->nr_frags; i++) {
> -				xdp_page = skb_frag_page(&shinfo->frags[i]);
> +		case VIRTNET_XDP_RES_DROP:
> +			if (unlikely(xdp_page != page))
>  				put_page(xdp_page);
> -			}
> -		}
>  
> -		goto err_xdp;
> +			rcu_read_unlock();
> +			goto err_xdp;
> +		}
>  	}
>  	rcu_read_unlock();
>  
> -- 
> 2.32.0.3.g01195cf9f